Chairs may include lumbar supports. Examples of lumbar supports in chairs may be appreciated from U.S. Pat. Nos. 6,908,159, 6,575,530, 6,394,546, 6,079,785, 5,902,011, 5,791,733, 5,772,282, 5,611,598, 5,551,752, U.S. Patent Application Publication Nos. 2010/0141000, 2009/0218864 and 2003/0111886 and International Patent Application Publication No. WO/2010/068122. Typically, lumbar supports are attached to the back frame of a chair and are configured to engage the back skin of the chair back when a user leans back against the back skin. Some types of lumbar supports are configured to press against the back skin to force the back skin into a bowed shape. Other types of lumbar supports are configured to passively support a user's back by providing additional support to the back skin after a user has pushed the back skin sufficiently far enough to engage the lumbar support.
Many lumbar supports do not permit a user to adjust the amount of support provided by the lumbar support. For instance, many lumbar supports are simply pads that are permitted to be repositioned in a number of different locations, but provide the same support to the back skin at each position. While the different position may change the mechanical advantage of support provided by the lumbar support for some of these types of lumbar support, the lumbar support itself does not provide any adjustable amount of support to a user's back independent of the position of the lumbar support.
A new lumbar support is needed that may permit additional support to be provided to a user's back when sitting on a chair that provides a lower cost of manufacturing and easy use for the seated user. Preferably, the lumbar support is designed to permit the lumbar support to provide an adjustable amount of support so that a user may adjust the lumbar support to provide a desired amount of support.